Have you looked at the code in your responsive section I referred to? You may want to google how to create responsive css. It’s mostly changing fixed widths to percentages. Right now you have fixed widths that need to be percentages instead when viewed at certain sizes. It will take some effort on your end, but this can definitely be done.
Obviously I can’t do it all for you since this is a customization request (which goes beyond the scope of support). But I think you could figure out the concept by learning how responsive css works first and then adding the necessary code in the right places. If you don’t want to deal with the code part, then I’d just hire someone to develop it all for you.
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